JP3188210B2 - Centrifugal dehydrator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention accommodates the laundry therein the cage-like drum, a centrifugal dehydrator to perform draining dewatering or cleaning solvent of the laundry by rotating the drum ( Here, the term “centrifugal dehydrator” includes a solvent centrifugal dewatering device). Needless to say, the present invention can be used for a washing machine or a washing / drying machine which continuously performs washing, dehydration, and drying.

[0002]

2. Description of the Related Art A drum type centrifugal dehydrator has a structure in which washed laundry is accommodated in a basket-shaped drum, and the drum is rotated at a high speed about a horizontal axis. One of the major problems with this type of centrifugal dehydrator is that when the drum is rotated at high speed while the laundry is not evenly distributed on the inner wall of the drum, abnormalities occur due to imbalance in the mass distribution around the rotation axis. Vibration and abnormal noise are generated. In a commercially available drum type washer / dryer equipped with such a centrifugal dehydrator, a weight is mounted around an outer tub in which the drum is installed in order to suppress the abnormal vibration. For this reason, this type of conventional washer-dryer was very heavy, and the installation place was limited, and it was difficult to move and transport.

[0003] Several drum-type centrifugal dehydrators for solving the above-mentioned problem of abnormal vibration have conventionally been proposed. For example, in the centrifugal dewatering device described in Japanese Patent Application Laid-Open No. 6-254294, a method is disclosed in which laundry is uniformly distributed and arranged on the inner peripheral wall of the drum by low-speed rotation of the drum before performing the dehydration operation by high-speed rotation of the drum. . More specifically, first rotate the drum at low speed for a very short time,
Then, the laundry is dispersed by a combination of two-stage rotation control of rotating the drum at a rotation speed slightly higher than the rotation speed but sufficiently lower than the rotation speed during the spin-drying operation.

In the above prior art, a vibration monitoring sensor is installed on a pedestal portion of the apparatus as means for detecting uneven distribution of laundry inside the drum, and the rotation speed of the drum is increased to a high rotation speed for performing a dehydrating operation. When the vibration monitoring sensor detects abnormal vibration, the rotation speed is reduced.

[0005]

However, even if the method of controlling the rotation of the drum as in the above-mentioned prior art is used, the laundry is not always surely evenly distributed by one low-speed rotation of the drum. Therefore, the drum must be rotated at a high speed after trying to disperse the laundry by the low-speed rotation of the drum, and when abnormal vibration occurs, the rotational speed of the drum must be reduced again to re-disperse the laundry. If the dispersion of the laundry by the low-speed rotation of the drum and the detection of the eccentric load by the high-speed rotation of the drum are repeated a plurality of times in this manner, the dehydration time is prolonged.

Further, as described above, in the method of evenly distributing the laundry on the inner peripheral wall surface of the drum, when only one relatively heavy (eg, jeans) garment is stored in the drum, Even dispersion cannot be performed, and it becomes impossible to suppress abnormal vibration.

[0007] For example, Japanese Patent Publication No. Hei 7-1000009 discloses a centrifugal dehydrator for adjusting the balance by adding a weight to a part of the inner peripheral wall of the drum. In this conventional centrifugal dehydrator, when the weight reaches the highest position of the drum, the laundry is determined to be in a position facing the weight with respect to the drum rotation axis due to gravity, and both are balanced. The drum shifts from low-speed rotation to high-speed dehydration rotation. However, even by such a method, it is not always possible to shift to the high-speed spinning rotation with the weight and the laundry being surely balanced, and it is not possible to completely prevent abnormal vibration during the spinning operation. Of course, it would be possible to balance by imposing strict conditions such as storing a predetermined weight of laundry in the drum according to the weight of the weight,
This is not practical in an actual centrifugal dehydrator.

[0008] In view of the above problems, the applicant of the present application filed Japanese Patent Application No.
In JP-A-354520 and the like, a pocket-shaped liquid holding portion capable of temporarily holding water is formed in a part of a baffle of a drum, and a predetermined amount of water is injected into the liquid holding portion according to uneven distribution of laundry. Thus, a centrifugal dehydrator having a novel configuration for adjusting the balance of the entire drum has been proposed.

In the centrifugal dehydrator, the magnitude and position of the eccentric load can be detected based on the fluctuation component of the current flowing through the motor that drives the drum to rotate. More specifically, since the motor current has a fluctuation component corresponding to the load fluctuation of the torque, the amplitude value of the fluctuation component reflects the magnitude of the eccentric load, and the peak position of the fluctuation is deviated on the inner peripheral wall surface of the drum. It depends on the position where the core load exists.
The magnitude of the eccentric load is an index value for determining whether vibration or noise occurs during dehydration. Therefore, if the magnitude of the eccentric load cannot be detected with high accuracy, vibration or noise may occur during dehydration despite the determination that the eccentric load is small. Despite the load being sufficiently small, it is determined that the eccentric load is large, and it is not possible to shift to the dewatering operation, and the dewatering time may be prolonged.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem. It is an object of the present invention to improve the accuracy of detecting an eccentric load before the start of dehydrating operation, so that abnormal vibrations and abnormalities during dehydrating operation are improved. An object of the present invention is to provide a centrifugal dehydrator capable of suppressing noise more reliably.

[0011]

[Embodiment means and Invention The present centrifugal dehydrator of the present invention made to solve the above problems, make the drum accommodating a laundry within cage-like drum rotation A centrifugal dewatering device for dewatering the laundry by: a) a motor for rotating a drum; b) a rotational speed detecting means for detecting a rotational speed of the motor; and c) an eccentric load of the drum. The mode to detect
In the stage of maintaining the rotation speed of the
Te, the actual of the motor detected by the speed detecting means
Rotation speed control means for controlling the rotation speed of the motor so that the actual rotation speed, which is the rotation speed at the time, becomes the target rotation speed; and d) fluctuations in the drive current supplied to the motor by the rotation speed control means. Eccentric load detecting means for detecting the eccentric load of the drum, wherein the rotational speed control means is based on a difference between the target rotational speed and the actual rotational speed.
Relative speed component based on absolute speed component and fluctuation amount of actual rotation speed
Calculate the control amount for controlling the rotation speed by the sum of
And the eccentric load detected by the eccentric load detecting means is
When the ratio is large, the contribution ratio of the relative velocity component is increased .

[0012]

In the above centrifugal dehydrator according to the present invention,
First, the rotation speed control means calculates a control amount by a predetermined calculation method so that the actual rotation speed detected by the rotation speed detection means becomes the set target rotation speed, and the drive current is supplied to the motor based on the control amount. Supply. As a result, the drum rotates, and the laundry stored in the drum sticks to the inner peripheral wall of the drum due to centrifugal force and rotates. At this time, since the drive current flowing through the motor has a component corresponding to the variation of the load torque, it fluctuates substantially periodically mainly due to the eccentric load caused by the uneven distribution of the laundry on the inner peripheral wall surface of the drum. The eccentric load detecting means detects the magnitude of the eccentric load based on the fluctuation amplitude of the drive current.

When the eccentric load existing on a part of the inner peripheral wall of the drum is rotating together with the drum, when the eccentric load is lifted above the drum, the gravity acting on the eccentric load causes the drum to rotate in the reverse direction. Work in the direction. When the eccentric load passes through the highest position of the drum and starts to fall downward, gravity acts in a direction for rotating the drum forward. As described above, while the drum makes one rotation, a force that varies the rotation speed according to the position of the eccentric load acts, but in a range where the amount of eccentricity is small,
Since the friction between the shaft that horizontally supports the drum and the bearing that supports the shaft is relatively large, the influence on the fluctuation of the rotation speed is small. However, when the amount of eccentricity increases to a certain extent, the influence of the friction decreases to a negligible level,
The fluctuation of the rotation speed due to the eccentric load increases.

For this reason, unless the above control amount is calculated so as to suppress the fluctuation of the rotation speed due to the eccentric load, it becomes difficult for the control to follow the fluctuation of the rotation speed, and the motor drive current with respect to the increase of the eccentric amount becomes difficult. The increase in the fluctuation amplitude becomes small. Therefore, when the amount of eccentricity is large, when calculating the control amount, the calculation method of the control amount is changed so as to increase the contribution ratio of the relative speed component. As a result, the fluctuation of the motor drive current increases following the fluctuation of the rotation speed, and the detection accuracy of the eccentricity is improved.

[0016]

[0017]

[0018]

[0019]

[0020]

According to the centrifugal dehydrator according to the present invention, there is provided a centrifugal dehydrator for detecting the amount of eccentricity of a drum based on a variation in a current flowing through a motor for rotating the drum.
According to the range of the amount of eccentricity, a motor speed control method is selected such that the increase in the variation of the motor drive current with respect to the increase in the amount of eccentricity is large. Therefore, a wide range of eccentricity can be detected with high accuracy. Therefore, by using the eccentric load detected in this way, the amount of eccentricity can be reliably determined, and abnormal vibration and abnormal noise can be reliably prevented from occurring during the dehydration operation. In addition, since the eccentricity is not erroneously determined to be large even though the eccentricity is sufficiently small, it is possible to promptly shift to the spin-drying operation and prevent the spin-drying time and the washing time from being prolonged. can do.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the centrifugal dehydrator according to the present invention will be described below with reference to the drawings. First, the structure of a drum type washing machine having a centrifugal dehydrator according to the present invention will be described with reference to FIGS. FIG. 1 is a side sectional view of the washing machine, and FIG. 2 is a rear perspective view showing a main part of the washing machine.

An outer tub 32 is suspended by a spring 34 and a damper 36 inside the outer case 30, and a drum 38 for containing laundry is supported by a main shaft 40 inside the outer tub 32.
A number of water holes 42 are provided in the peripheral wall of the drum 38, and water supplied to the outer tub 32 flows into the drum 38 through the water holes 42, and conversely, The water dehydrated from the water is scattered to the outer tub 32 through the water passage hole 42.

On the inner circumference of the drum 38, four baffles 44 are provided at positions each having a rotation angle of 90 degrees for scraping up the laundry with the rotation. One of the baffles 44 also serves as a balancer 46 for retaining water therein. On the back surface of the drum 38, a substantially disk-shaped water guide chamber 48 having a large water injection opening 50 on the inner peripheral side of the circumference around the main shaft 40 is provided. In the water guide chamber 48, a water injection hole 52 communicating with the balancer 46 is formed on the drum 38 side, and a drain hole 54 is formed on the outer tank 32 side facing the water injection hole 52 approximately 180 degrees with respect to the main shaft 40. I have. Outer box 30
A door 56 for opening and closing the front opening of the outer tub 32 is provided on the front surface of the outer tub 32, and laundry is stored in the drum 38 by opening the door 56.

The main shaft 40 has a bearing 58 mounted on the outer tub 32.
, And a main pulley 60 is attached to the tip. A motor 62 is disposed on the lower surface of the outer tub 32, and the rotational driving force of the motor 62 is a motor pulley 64,
The power is transmitted to the main pulley 60 via the V-belt 66. In addition, water supplied to the water supply port 68 from an external tap, etc.
Water is injected into the outer tub 32 through the water supply valve 70, and is discharged from the water injection nozzle 74 provided in the outer tub 32 through the balance water injection valve 72. On the other hand, the water accumulated in the outer tub 32 is discharged outside through a drain port 78 opened and closed by a drain valve 76. An opening is provided on the ring portion of the main pulley 60 at one location on the circumference, and a light emitting unit 801 and a light receiving unit 802 are arranged on both sides of the ring portion. Thus, the light emitted from the light emitting unit 801 only once during the rotation of the drum 38 reaches the light receiving unit 802 through the opening. A rotation sensor described later outputs a detection signal (rotation marker) synchronized with the rotation of the drum 38 based on the light receiving signal.

Next, water injection and drainage to the balancer 46 will be described in detail with reference to FIG. FIG. 3 is a schematic diagram showing the operation state of the balancer 46 and the water guide chamber 48. When the water is discharged from the water injection nozzle 74 while the drum 38 is rotating at a predetermined rotation speed or more, the discharged water enters the water guide chamber 48 through the water injection opening 50, and the rear wall of the drum 38 is removed. It moves to the outer peripheral side by centrifugal force while being transmitted.
Then, as shown in FIG. 3A, the water adheres to and is held on the inner side of the outer peripheral wall of the water guide chamber 48 by centrifugal force. In addition,
Since the water injection opening 50 has a large area, even if the direction of fall of the water discharged from the water injection nozzle 74 varies due to a variation in water pressure or the like, most of the water surely jumps into the water guide chamber 48.

The balancer 46 is a hollow body that extends further outward than the water guide chamber 48 with respect to the main shaft 40. Therefore, the water injected into the water guide chamber 48 enters the balancer 46 through the water injection hole 52 by centrifugal force, and the water is injected into the water guide chamber 48 as shown in FIG.
As shown in (b), the balancer 46 is attached and held on the outer peripheral wall side, that is, on the inner peripheral wall surface of the drum 38. In addition, a drain hole 54 is also opened on the outer peripheral side of the water guide chamber 48, and water escapes from the water guide chamber 48 through the drain hole 54, but the amount of drain water is compared with the amount of water injected into the water guide chamber 48. And very few.

When discharging the water accumulated in the balancer 46, the balancer 46 is stopped and held at the highest position on the rotation circumference. Then, since the centrifugal force acting on the water in the balancer 46 is lost, the water flows out to the water guide chamber 48 through the water injection hole 52 as shown in FIG. The accumulated water flows out to the outer tub 32 through the drain hole 54 located at the lowest position on the rotation circumference. Water injection hole 5
Although the opening area of the drain holes 2 and the drain holes 54 is small, the water in the balancer 46 and the water guide chamber 48 is completely drained to the outer tank 32 if the balancer 46 is kept at the above position for a while.

Next, the electrical configuration and operation of the centrifugal spin-dryer in the washing machine will be described with reference to FIG.
Control unit 10 mainly composed of microcomputer
Is composed of a central control unit 11, a phase control unit 12, an eccentric load detection unit 13, and a water injection control unit 14. The central control unit 11 includes a memory in which an operation program for performing the dehydration operation is stored in advance, receives information on the magnitude and position of the eccentric load from the eccentric load detecting unit 13, processes the information as described below, The target rotation speed Np of the motor corresponding to the drum rotation speed is instructed to the phase control unit 12.

The motor drive unit 20 includes an AC power supply 201 and an AC switch unit 202, and functions as a rotation speed control unit of the motor 62 together with the phase control unit 12. The motor 62 is provided with a rotation speed detector 22, and an index value corresponding to an actual rotation speed (hereinafter referred to as “actual rotation speed”) is fed back to the phase control unit 12.

The motor current detecting section 21 includes the motor driving section 2
From 0, the drive current supplied to the motor 62 is detected, converted into a voltage value, and provided to the eccentric load detection unit 13. FIG. 5 is a diagram illustrating an example of the time variation of the motor current. In the figure, a rotation marker M is a marker indicating one rotation cycle of the drum 38 obtained by the rotation sensor 23 attached to the drum 38. If an eccentric load exists on the drum 38, the motor current has a fluctuation component corresponding to the eccentric load as shown in FIG. The fluctuation of the motor current corresponds to the fluctuation of the load torque of the motor 62, and the maximum peak of the motor current appears when the load torque becomes maximum within one rotation period of the drum 38. The fluctuation amplitude L of the motor current corresponds to the magnitude of the eccentric load (the amount of eccentricity). Therefore, the correspondence between the fluctuation amplitude L and the eccentricity is checked in advance and stored in a memory, and the eccentricity is obtained from the fluctuation amplitude L using this correspondence.

When a signal having a motor current variation component as shown in FIG. 5 is input, the eccentric load detecting section 13 has a maximum peak and a minimum at every interval of the rotary marker M, that is, every one rotation period of the drum 38. Detect the peak. Then, the difference (fluctuation amplitude L) between the maximum and minimum peaks is calculated, and the amount of eccentricity is obtained by referring to the correspondence stored in the memory.
Further, the position of the eccentric load on the inner peripheral wall surface of the drum 38 is detected based on the timing at which the maximum peak appears (for example, the delay time from the immediately preceding rotation marker M).

Next, the operation of the rotation control of the motor 62 centering on the phase control unit 12 and the motor drive unit 20 will be described with reference to FIG.
It will be described in detail with reference to FIG. The phase control unit 12 calculates the control angle α from the index value Np corresponding to the target rotation speed and the index value Nr corresponding to the actual rotation speed, as described later, and inputs the control angle α to the AC switch unit 202. 6 from the AC power supply 201.
A sinusoidal single-phase AC current as shown in FIG. The AC switch unit 202 is composed of a gate-controlled semiconductor switch such as a triac,
The alternating current is turned on and off according to the control angle α. That is, as shown in FIG. 6B, a pulse signal is generated at a position delayed by the control angle α from the reference position at the phase angle of 0 °, the current is interrupted during the phase angle of 0 ° to α, and the phase signal is generated. Angle α
The ON / OFF of the gate control type semiconductor switch is controlled so as to allow a current to pass during a period of up to 180 degrees. As a result, an intermittent current in a range indicated by oblique lines in FIG. 6C is supplied to the motor 62 as a drive current. Accordingly, the phase control unit 12 decreases the control angle α when accelerating the motor 62, and increases the control angle α when decelerating the motor 62.

In the centrifugal dehydrator according to the present embodiment, the phase controller 12 determines the control angle α based on the following equations (1) to (4). Control angle α = control angle one pulse before + control angle change Δα (1) control angle change Δα = absolute speed component β + relative speed component γ (2) absolute speed component β = (target rotation speed pulse width− (Actual rotation speed pulse width) / constant a (3) Relative speed component γ = (actual rotation speed pulse width one pulse before—actual rotation speed pulse width) / constant b (4) where the pulse width is the rotation speed The motor 6 is detected by the detector 22.
This is the time width of a predetermined number of pulse signals obtained in one rotation period. The higher the rotation speed, the smaller the pulse width. For example, 10 times while the rotation speed detector 22 makes one rotation.
Pulse signals are obtained. Further, since the rotation speed of the motor 62 is normally reduced and transmitted to the drum 38, for example, if the reduction ratio is 1/3, 33 to 34 pulse signals are obtained during one rotation of the drum 38. Will be done.

In the above equations (1) to (4), the absolute velocity component β
Is a term based on the difference between the target rotation speed and the actual rotation speed,
The relative speed component γ is a term based on the amount of change in the rotational speed each time the motor 62 or the drum 38 rotates by a predetermined angle, and the control angle change Δα, that is, the control angle α, is determined by appropriately setting the constants a and b. The ratio of the contribution of the absolute velocity component β and the relative velocity component γ can be changed. In this type of conventional rotation control, reference data in a table format for determining the control angle α using the target rotation speed and the actual rotation speed as parameters is created and stored in a ROM or the like, and the target rotation speed and the actual rotation speed are stored. The value of the control angle α is obtained by giving the speed. For this reason, the control angle α is changed stepwise depending on the accuracy of the reference data, and the rotation speed of the drum is not always increased / decreased smoothly. However, in the present embodiment, the control angle α
Is calculated, the control angle α can be finely changed, and the rotation speed of the drum rises and falls more smoothly.

Next, a procedure of controlling the entire dehydration process in the washing machine having the above configuration will be described with reference to the flowchart of FIG. In the following description, a numerical value when the diameter of the drum is set to 470 mm is taken as an example, but it is apparent that a case where the drum diameter is different can be dealt with by appropriately changing the numerical value of each rotation speed. is there.

When the washing process is completed and the dewatering process is started, the laundry in the drum 38 is piled up on the bottom thereof. At this time, no water enters the balancer 46, and the drum 38 itself has no eccentric load. When the start of the dehydration process is instructed by the user from the operation unit 24,
The motor 62 is started, and an eccentric load detection process described later is executed (step S1). At this time, the drum 38
The laundry is rotated in one direction at a rotation speed N1 (for example, about 130 rpm) higher than the rotation speed at which the centrifugal force acting on the laundry and gravity are balanced.

When the eccentricity amount and the eccentricity position are detected by the eccentric load detection processing in step S1, the central control unit 11 determines whether the eccentricity amount is equal to or less than a predetermined value a. (Step S2). When it is determined in step S2 that the amount of eccentricity is equal to or smaller than the predetermined value a, it can be determined that vibration and noise are small even if the dehydration operation is performed in that state. Therefore, the process proceeds to step S6, where the rotation speed of the drum 38 is increased to a predetermined high-speed rotation speed N2. Thereby, the water that has permeated the laundry is scattered by the centrifugal force and dehydrated. Here, the high-speed rotation speed N2 is 1000 rpm
However, in order to protect the laundry that is liable to damage the cloth, the upper limit is limited to a washing course specified by the user (for example, a blanket washing course, a dry-only clothes washing course, etc.). Is preferred.

If it is determined in step S2 that the amount of eccentricity is larger than the predetermined value a, then the eccentric position is changed to the balancer 46.
It is determined whether or not the position is within a predetermined range near the position facing 180 degrees (step S3). The predetermined range is set to the balancer 46 with respect to the main shaft 40 in consideration of the detection error of the eccentric position.
Is set to an appropriate width centering on a rotation position facing 180 degrees. If it is determined in step S3 that the eccentric position is within the predetermined range, it can be determined that the balance adjustment of the drum 38 can be performed by injecting water into the balancer 46. Then, the process proceeds to step S5, in which the balance water injection operation described later is executed to achieve the balance, and then the dehydration operation is performed (step S6).

When it is determined in step S3 that the eccentric position is not within the predetermined range near the position facing the balancer 46, a loosening operation described later is executed in order to rearrange the laundry (step S4). .

FIG. 8 is a flowchart showing an example of the rotation control during the loosening operation in step S4. In the loosening operation, first, the rotation of the drum 38 is temporarily stopped or reduced to a degree at which it is almost stopped (step S41). Next, the rotation speed of the drum 38 during the washing process (for example, about 55 rpm)
m), the drum 38 is rotated leftward (step S42), and then the rotation direction is reversed to rotate the drum 38 rightward at the same rotation speed (step S43). Then, the left-right inversion is repeated until a predetermined time elapses (step S4).
4), end the loosening operation. Thereby, the drum 38
Since the laundry is agitated inside, air enters into the gap between the laundry, and the entangled laundry is loosened, and the laundry is easily separated from each other. For this reason, when the rotation speed of the drum 38 is raised to the low rotation speed N1 next, returning from step S4 to S1, the loosened laundry is easily dispersed evenly on the inner peripheral wall surface of the drum 38, and the eccentric amount is increased. Is likely to be less than or equal to the predetermined value a.

FIG. 9 is a flowchart showing an example of the control of the balanced water injection operation in step S5. In the balanced water injection operation, the rotation speed of the drum 38 is set to N1 (1
30 rpm) while detecting the amount of eccentricity (step S
51), a water injection valve 7 for balance by the water injection control unit 14
2 is released (step S52). As a result, water is discharged from the water injection nozzle 74 and the balancer 46 is discharged as described above.
The water gradually enters and is held in the balancer 46 while being attached to the inner peripheral wall of the drum 38 by centrifugal force. At the same time, the eccentric amount that gradually changes is detected by the eccentric load detection unit 13, and the central control unit 11 determines whether the eccentric amount is equal to or less than a predetermined value b (step S53).

The laundry in the drum 38 rotates while being completely pressed against the inner peripheral wall surface by the centrifugal force, while the amount of water in the balancer 46 gradually increases and the weight increases. The fluctuation amplitude L of the motor current as shown in FIG. If it is determined in step S53 that the eccentric amount is equal to or smaller than the predetermined value b, the water injection control unit 1
4, the balance water injection valve 72 is closed (step S54). As a result, the increase in the water inside the balancer 46 stops, and the eccentric load due to the uneven distribution of the laundry and the balancer 4
The amount of eccentricity of the entire drum 38 becomes small due to the balance with the water in 6.

Next, the operation of the eccentric load detection processing in step S1, which is a feature of the present invention, will be described in detail with reference to the flowchart of FIG. First, the phase control unit 12 sets the initial control angle α ₀ to 90 degrees, whereby the motor drive unit 2
The drive current obtained at 0 is supplied to the motor 62 (step S11). Next, in the phase control unit 12, the pulse signal obtained when the motor 62 is rotating is
2 is determined (step S1).
2). When it is determined in step S12 that the pulse signal has not been input, it can be determined that the motor 62 is not rotating. Therefore, the control angle α is reduced by one degree in order to increase the drive current (step S13), and it is determined again whether or not the pulse signal has been input. Therefore, the control angle α is corrected to be smaller by one degree until the motor 62 starts rotating by the processing of steps S12 to S13.

If it is determined in step S12 that a pulse signal has been input, the constant a in equations (1) to (4) is used.
And b are set to 1000 and 500, respectively, and the phase control is performed using the rotation speed of the motor 62 such that the rotation speed of the drum 38 becomes 130 rpm as the target rotation speed (step S14). Thus, the rotation speed of the drum 38 is maintained at around 130 rpm. After several seconds elapse so that the rotation speed becomes stable, the eccentric load detection unit 13
5, the eccentricity amount and the eccentric position are calculated from the fluctuation amplitude L and the peak position based on the fluctuation waveform as shown in FIG. 5 detected by the motor current detection unit 21 (step S15).

FIG. 11A shows that a = 1000 and b = 50.
Fluctuation amplitude L when phase control is performed by setting to 0
It is a figure which shows the correspondence of an eccentricity with an eccentricity. Under the conditions of the phase control, the slope of the fluctuation amplitude L with respect to the eccentric amount is almost linear and steep in the range where the eccentric amount is 500 g or less, so that the eccentric amount can be accurately obtained. However, when the amount of eccentricity exceeds 500 g, the inclination becomes gentle and the detection error of the amount of eccentricity increases.

The reason is considered as follows. That is, when the eccentric load rotates with the rotation of the drum 38, a swinging force is applied to the main shaft 40 supporting the drum 38. Therefore, the frictional force between the main shaft 40 and the bearing 58 is reduced by the eccentric load. Is larger than when no exists. When trying to lift the eccentric load above the drum 38, the gravity acting on the eccentric load acts in the opposite direction to the rotation of the drum 38, as shown in FIG.
It works to slow down the rotation speed. On the other hand, when the eccentric load passes through the highest position of the drum 38 and is going to be lowered, the gravity acting on the eccentric load is in the same direction as the rotation of the drum 38, as shown in FIG. As a result, the rotation speed of the drum 38 is increased. However, in the range where the amount of eccentricity is relatively small, the above-mentioned frictional force is relatively large, so that the influence of the force for promoting the change in the rotation speed due to gravity is small.

In the above equations (1) to (4), the relative velocity component γ
Is a term corresponding to the amount of change in the rotation speed of the motor 62. The larger the constant b, the smaller the control angle α for the amount of change.
As described above, for example, assuming that 34 pulse signals are obtained from the rotation speed detector 22 during one rotation of the drum 38, the relative speed component γ is the fluctuation of the rotation speed every time the drum 38 rotates about 11 degrees. It will be according to. That is, it reflects the amount of change in the rotational speed each time the eccentric load rotates 11 degrees on the inner circumference of the drum 38.

As described above, in a range where the influence of the frictional force is large, that is, in a range where the amount of eccentricity is small, such a fluctuation in the rotation speed is small, and therefore the constant b is set relatively large. However, when the amount of eccentricity is large and the influence of the frictional force is so small that it can be ignored, the fluctuation amount of the rotational speed due to the eccentric load becomes relatively large, and as described above, the term of the relative speed component γ is small. The follow-up characteristic to the fluctuation of the rotation speed is deteriorated. As a result, as shown in FIG. 11A, the variation of the motor current with respect to the variation of the eccentric amount is reduced.

Therefore, in the range where the amount of eccentricity is large as described above, when calculating the control angle α, the contribution of the absolute velocity component β is reduced and the contribution of the relative velocity component γ is increased. That is, in the above equations (1) to (4), the constant a is increased while the constant b is decreased. Thereby, even when the phase is controlled so as to maintain the same rotation speed, the follow-up characteristic with respect to the fluctuation of the rotation speed is improved.

Referring back to FIG. 10, the above-described step S
After the eccentricity is once detected at 15, the eccentricity is 500 g
It is determined whether or not this is the case (step S16). When it is determined in step S16 that the amount of eccentricity exceeds 500 g, the phase control unit 12 changes the constants a and b to 2000 and 250, respectively, and then the rotation speed of the drum 38 becomes 130 rpm. Motor 6 like
The phase control is performed using the rotation speed 2 as the target rotation speed (step S17).

FIG. 11B shows that a = 2000 and b = 25.
Fluctuation amplitude L when phase control is performed by setting to 0
It is a figure which shows the correspondence of an eccentricity with an eccentricity. Under the condition of such a constant, the follow-up characteristic to the fluctuation of the rotational speed is improved in the range where the amount of eccentricity is large as described above, so that the inclination becomes almost linear and steep, and the amount of eccentricity is accurately detected. be able to.

The drum 38 is controlled under the phase control under the above conditions.
Is rotating, the eccentric load detection unit 13 calculates the eccentric amount and the eccentric position again based on the fluctuation waveform of the motor current (step S18). Then, instead of the eccentricity and the eccentricity detected in step S15, the newly detected eccentricity and the eccentricity are used.

Therefore, by the above series of processing, phase control is performed based on different constants when the amount of eccentricity is less than 500 g and when the amount of eccentricity is more than 500 g.
A wide range of eccentricity can be accurately detected.

In the above embodiment, the control angle α for controlling the phase of the motor is calculated by the equations (1) to (4).
The correspondence relationship between the target rotation speed and the actual rotation speed and the control angle change Δα may be quantified in a table format and stored in a memory. That is, the control angle change Δα for performing the phase control in the range where the eccentricity is small.
And a second table for obtaining a control angle change Δα for performing phase control in a range where the amount of eccentricity is large are prepared in the memory, respectively. First, refer to the first table. The control angle α is obtained by performing phase control to detect the eccentric load. If the eccentric amount is 500 g or more in step S16, the control angle α is obtained by referring to the second table. Phase control to detect the eccentric load again.

In the above embodiment, the rotation speed of the motor is controlled to be constant by the phase control. However, for example, the pulse width is changed to adjust the drive current supplied to the motor.
The present invention can also be applied to a configuration in which the rotation speed of a motor is controlled to be constant by WM control.

Although the above embodiment has been described with reference to a drum type washing machine, it is apparent that the present invention can be applied to a dry cleaner using a petroleum solvent or the like.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a drum type washing machine having a centrifugal dehydrator according to an embodiment of the present invention.

FIG. 2 is a rear perspective view of a main part of the washing machine of FIG. 1;

FIG. 3 is a schematic diagram showing a state of injecting and discharging water to and from a balancer in the centrifugal dehydrator of the present embodiment.

FIG. 4 is an electric block diagram of the centrifugal dehydrator of the present embodiment.

FIG. 5 is a diagram illustrating an example of a change in motor current due to the influence of an eccentric load.

FIG. 6 is a waveform chart for explaining a motor speed control operation in the embodiment.

FIG. 7 is a flowchart showing a control operation at the time of a dehydration operation in the embodiment.

FIG. 8 is a flowchart showing a control operation at the time of a dehydration operation in the embodiment.

FIG. 9 is a flowchart showing a control operation at the time of a dehydration operation in the embodiment.

FIG. 10 is a flowchart illustrating an eccentric load detection operation according to the present embodiment.

FIG. 11 is a diagram showing a correspondence relationship between a fluctuation amplitude of a motor current and an eccentricity amount.

FIG. 12 is a schematic diagram showing a rotation state of a drum when an eccentric load exists.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Control part 11 ... Central control part 12 ... Phase control part 13 ... Eccentric load detection part 14 ... Irrigation control part 20 ... Motor drive part 201 ... AC power supply 202 ... AC switch part 21 ... Motor current detection part 22 ... Rotation speed Detector 23 ... Rotation sensor 38 ... Drum

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Shuji Hotta 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Inside Sanyo Electric Co., Ltd. (72) Inventor Tetsuo Harada 2-5-2 Keihanhondori, Moriguchi-shi, Osaka No. 5 Sanyo Electric Co., Ltd. (56) References JP-A-9-10481 (JP, A) JP-A-9-10482 (JP, A) JP-A-8-309077 (JP, A) JP-A-4- 250196 (JP, A) JP-A-3-66197 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) D06F 49/04 D06F 33/02 H02P 5/402 301

Claims (1)

(57) [Claims] 1. A centrifugal dehydrator for performing dehydration of accommodating a laundry within cage-like drum the laundry by rotating the drum, a motor for rotating the a) drum, b) the motor Rotation speed detecting means for detecting the rotation speed of the drum ; c) detecting the eccentric load of the drum;
In the stage of maintaining the rotation speed of the
Te, the actual of the motor detected by the speed detecting means
Rotation speed control means for controlling the rotation speed of the motor so that the actual rotation speed, which is the rotation speed at the time, becomes the target rotation speed; and d) fluctuations in the drive current supplied to the motor by the rotation speed control means. Eccentric load detecting means for detecting the eccentric load of the drum based on the rotational speed.
Of the absolute speed component and the actual speed based on the difference from the speed
The rotation speed is controlled by the sum of the relative speed component based on the fluctuation amount.
Control amount for controlling the eccentric load detecting means.
When the detected eccentric load is large, the relative velocity component
A centrifugal dehydrator characterized by increasing the contribution ratio of water.